Method and means for indicating suspended matter in gases.



W. A. SCHMIDT.

METHOD AND MEANS FOR lNDiCATING SUSPENDED MATTER iN GASES. APPLICATIONmen mnjau. 1913.

1,168,227,, Patented Jan. 11, 1916.

WITNESSES INVENTOR 010% (2.5M W7 W M O/1M1? 1L ATTO RN EY WALTERA..SCH1VIIDT, 01 LOS ANGELES, CALIFORNIA, ASSIGNOE T0 INTERNATIONALPRECIPITATION COMPANY, OF L05 ANGELES,

CALIFORNIA.

METHOD AND MEANS FOR INDICATI NG' SUSPENDED MATT IN GA$ES.

To all whom it may concern:

Be it known that I, WALTER A. SCHMIDT, a citizen of the United States,residing at Los Angeles, in the county of Los Angeles and State ofCalifornia, have invented a new and useful Method and Means forIndicating Suspended Matter in Gases, of which the following is aspecification.

This invention relates tomeans for indicating the presence and amount ofsmoke, fumes, dust, mist, or other suspended matter in gases.

The invention is particularly applicable in connection with stacks orwaste fines of furnaces and kilns, and the main object of the inventionis to provide for indicating the amount of smoke or suspended matter inthe gases passin in such stacks or flues.

I have discovere that an electrical discharge into air or gas isdiminished or choked when suspended particles are brought into the pathof the discharge, the choklng effect increasing with the amount ofsuspended matter present. My invention is based on this discovery andconsists essentially in means for passing an electrical discharge intoor through the gas to be tested, and means for indicating the quantityor energy of the discharge.

The accompanying drawings illustrate embodiments of my invention, andreferring thereto: Figure 1 is an elevation of a stack, partly brokenaway, showing the application of my invention thereto, the circuitconnections being shown diagrammatically. Fig. 2 1s a vertical sectionof the set of electrodes for the indicator. Fig. 3 is a vertical sectionof another .form of the electrodes. Figs. 4 and 5 are elevations ofother forms of the electrodes. Fig. 6 is a diagram of another form ofthe invention.

In Fig. 1, I have illustrated the application of my invention to astack, chimney or flue, indicated at 1, for carrying o the waste gasesfrom a furnace or kiln. Electrodes 2 and 3 are provided in the stack orflue, or near the outlet thereof, in such position that a part or all ofthe gas passing through the stack or flue is conducted be tween theelectrodes. One, at least of such electrodes should be of a character topromote silent discharge of electricity therefrom through or into thegas. For this purpose, the electrode 2 may consist of a pointed rodSpecification of Letters Patent.

' the discharge Patented Jan. 11, 19116.

Application filed January 30, 1913. Serial No. 745,082.

or wire, as shown in Fig. 2, the other electrode, 3, being in the formof a plate or sheet of conducting material. Electrodes 2 and 3 areconnected to any suitable means for producing high tension electricaldischarge from the electrode 2. Such means may consist of a step-uptransformer 5, whose primary winding is connected to the wires 6 and 7of an alternating current supply circuit, and whose secondary winding isconnected to the wires 8 and 9, leadingS to the respective electrodes 2and 3.

uitable means are provided for measuring or indicating the magnitude ofthe discharge, foi example, a millimeter 10 may be included in theenergizing circuit .for the transformer 55, to show the current beingused in the apparatus, or a wattmeter 11 may be connected to thiscircuit to measure the energy consumed. By reading either or both ofthese instruments, an estimate may be made of the magnitude of thedischarge. These instruments may be placed in the furnace room, office,or other location where information is desired as to the condition ofthe gases escaping through the stack or flue.

The operation of this embodiment of my invention, is as follows:Alternating current is supplied through the circuit 6, 7, to thetransformer 5, causing a high tension alternating current to be producedin the secondary of said transformer, this current being delivered tothe electrodes 2 and 3. 'If there is substantially no dust or othersuspended matter in the gas between the electrodes, there will be acertain amount of discharge or passage of electricity from theelectrodes into or through the gas between or adjacent to theelectrodes, the amount of being dependent on the temperature of the gas,and the size and configuration of the .electrode system. If now, dust orother suspended matter is introduced into the gas between theelectrodes, the condition of the gas being otherwise unchanged, thesuspended particles adjacent to the discharging electrode become chargedsimilarly to that electrode, thereby reducing the potential gradient inthe field adjacent to said electrode and correspondingly reducing orchoking the discharge, the discharge being eventually reduced by anamount depending on the amount of suspended matter present,

CALIFORNIA, A. CORPORATION OF charges on the suspended particles bysuccessive impulses, but by' using instruments 10 or 11 of sufficientsensitiveness, the differential effect due to charging action may beindicated with sufiicient distinctness for the purpose of thisinvention. By using low frequency alternating current, the chargingaction and the resultant indication on the testin instrument may beincreased. In case the alternating current used is of such highfrequency that a satisfactory indication is not obtained, a rectifiermay be included in the circuit of the electrodes, as shown at 13 in Fig.6. I prefer, however, to dispense with the rectifier when possible,

for the sake of simplicity, and ease, and

economy of installation and operation of the apparatus. s

In carrying out this invention it is essential, in order to pro uce thestated results, that the potential difierence applied to the electrodesshould be sufficient to produce a silent discharge," but not sufficientto produce a disruptive discharge or sparking, in any material amount,between the electrodes, the operation as described depending on thevariation of the silent discharge by reason of the presence of suspendedmatter. Instead of a pointed electrode, a wire electrode may be used forthe discharging side, as indicated at 12 in Fig. 3, or anyother suitableform of electrode may be used. As shown in Figs. 4 and 5, both of theelectrodes may be adapted to produce or promote discharge, theelectrodes being both pointed as at 2 in Fig. 4, or both formed of wire,as at 12,- in Fig. 5. With such an arrangement the action abovedescribed takes place at each electrode.

What I claim is: 1. Means for indicating the amount of incest}comprising electrodes,

for directing a current of gas between theelectrodes, a high tensionelectric circuit connected to said electrodes and provided with meansfor applying high potential difference to said electrodes to producesilent discharge into the gas between the electrodes, and currentindicating means responsive to the current in said high tension circuit,due to said silent discharge.

2. Means for indicating the amount of suspended matter in gases,comprising electrodes, means for directing a current of gas between theelectrodes, a high tension alternating current circuit connected to saidelectrodes to produce a silent discharge therebetween, a transformerhaving its secondary connected to said high tension circuit, analternating current supply circuit connected to the primary of saidtransformer, and a current indicating means in said supply circuit toindicate the amount of silent discharge between the electrodes.

3. The method of indicating the amount of suspended matter in gases,which consists 1n causing acurrent of such gases to pass betweenelectrodes maintained at a high potential difierence, suflicient toproduce silent discha ge into the gas but not sufficient to producedisruptive discharge in material amount between the electrodes, andmeasuring the amount of such discharge.

. 4. The method of indicating the amount of suspended matter in gases,which consists in causing the gas to pass between electrodes, applyingto said electrodes high tension alternating electric potentialdifference, suflicient to cause silent discharge into the gas betweenthe electrodes, but not sutlicient to cause disruptive discharge inmaterial amount between the electrodes, and measuring the amount of suchsilent discharge.

In testimony whereof, I have hereunto set my hand at Los Angeles,California, this 24th day .of January, 1913.

. WVALTER A. SCHMIDT.

In presence of 1 F. M. MOSHER, WM. N. DREW.

